This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The RIVUR study is a randomized, double-blind, placebo-controlled, multi-center study that will enroll children with febrile/symptomatic urinary tract infection (F/S UTI) and vesicoureteral reflux (VUR). Participants are randomized to receive placebo or study drug (i.e. Sulfamethoxazole-Trimethoprim, the standard UTI prophylactic antibiotic), and are monitored for a 2 year period to evaluate the development of renal scarring and recurrent UTIs. Blood and urine specimen collection, processing, and packaging services were requested from the CNMC Pediatric GCRC for this clinical research study being conducted by the CNMC Division of Urology.